Many of the resources below are free or very low cost, and are sure to be useful to a lot of designers and developers out there.
As always, if we've missed something you think should have been included, please let us know in the comments. And if you have an app or other resource you'd like to see included next month, tweet it to @cameron_chapman for consideration.
Duo is a web browser that lets you view both mobile and desktop versions of responsive websites you're designing. It's available as a bookmarklet, or as a standalone Mac program.
TimeTracker is a software-integrated time tracking app that offers automatic time capture, real-time analytics, and more. The free Basic account works with Adobe CS/CC, while paid accounts offer up additional software integration.
Coment.me makes it incredibly easy to comment or otherwise provide feedback on any URL. Just enter the website address, specify the width you'd like the page returned, and then comment, draw, or do whatever else you'd like before sharing the results.
Adaptive Backgrounds is a jQuery plugin for extracting colors from an image and applying those colors to the parent element. It's an easy way to make your background match your images.
Layrs Control is a free Photoshop extension to improve your workflow. You can edit layer names, remove unused effects, delete empty layers, and more.
Typing.io is a typing practice web app specifically for programmers, which will help you with mastering all those funky characters that appear in code but don't show up in many other places.
A Pocket Guide to Master Every Day's Typographic Adventures
This Pocket Guide to Master Every Day's Typographic Adventures offers up excellent guidance for all sorts of typographic questions you may face on a daily basis, from how to mix typefaces to choosing font size and line height and much more.
Passweird is a complex password generator that creates "utterly repulsive" passwords that no one would want to steal.
Origami is a Quartz Composer toolkit for design prototyping. It makes it easy to create interactive prototypes, without the need for any programming.
Myth is a preprocessor, like a CSS polyfill. It lets you write pure CSS without worrying about things like slow spec approval or slow browser support.
Social Kit is a Photoshop plugin for creating cover images, profile pictures, ad banners and more for your favorite social platforms, including Facebook, Google, Twitter, and YouTube.
Typecsset is a Sass library for setting type on the web, with an automatic, pixel-perfect, baseline grid that's easy to use.
Readymag is a simple web publishing tool for any kind of digital storytelling, from presentations to rich media magazines and microsites. It's cross-browser compatible and doesn't require any coding skills.
Writer Pro is a professional writing suite that includes note-taking, writing, and editing tools. It's under $20 for either OS X or iOS.
Planetary.js lets you create fully customizable, interactive globes for the web. It includes tools for displaying animated "pings" anywhere on the map, along with mouse drag and zoom support.
Picjumbo is a collection of totally free stock photos that you can use for your personal or commercial works. There are a variety of categories to choose some, with more photos added every day.
The Best Freelance Tools of 2013
The Best Freelance Tools of 2013 is a curated collection of tools from the past year that are certain to be incredibly useful for designers and other freelancers. It includes tools for finding clients, dealing with money, remote communication, and more.
Dillinger is a cloud-enabled HTML5 Markdown editor that's based on Ace Editor, Bootstrap, Marked, node.js, and more.
Pinegrow Web Designer
Pinegrow is an app for Windows and Mac that makes it fast and easy to mockup and design web pages with (or without) Bootstrap, multi-page editing, and Less.
Makeappicon generates all the icon sizes you need for iOS and Android with just one click.
Black Tie offers a collection of free Bootstrap themes that are actually good-looking. There are themes for app landing pages, contact pages, and much more.
Really Simple HTML Email Template
This Really Simple HTML Email Template is an easy to use template for creating your own HTML emails. It can be used, modified, and copied as you wish.
Asfalto is a free distressed display font designed by Fernando Forero. It comes in all caps, yet remains readable even at smaller sizes.
Hallo Sans (free)
Hallo Sans is a stylized sans serif typeface that comes in light, regular, and black weights.
Barokah is a free uppercase and lowercase display handwriting font that's perfect for things like comic books. It comes in regular and bold weights.
Odin Rounded (free)
Odin Rounded is a free experimental font with a clean, linear look. It comes in three weights: regular, bold, and light, with support for opentype features.
Purbacala is an ornate, decorative typeface with a handdrawn look. It comes in inline, regular, and bold styles.
Love Hearts ($20)
Love Hearts is a set of calligraphic ornaments and frames, including patterns and seamless borders, all in OTF format.
Rodian Serif ($10)
Rodian Serif is a modern rounded font in six styles, revisited by Jan-Christian Bruun. It comes in light, regular, and bold weights, as well as three matching stencil weights.
Hadron is a display typeface with two variants: a standard clean and clear sans serif, and an alternative with more pictographic letterforms.
Gluten is an experimental font family with irregular shadows that portray craftsmanship, and high contrast between thick and thin strokes in the letterforms.
The Serif Hand ($25)
The Serif Hand is a handwritten serif typeface that is generic, highly readable, and well-balanced, so it's versatile for any kind of design.
Know of a new app or resource that should have been included but wasn't? Let us know in the comments!